Virus release from vaccine plants or, more frequently, from infected farms may spread,
causing epidemics. One of the mechanisms by which virus dispersion can take place is transport by air. In these cases, a plume is formed downwind, similar to that found in gas releases. Although a number of authors have cited this qualitatively, very few papers have treated it in a quantitative way. In this article, a simulation code developed for risk analysis has been used to
forecast the dispersion of airborne virus at distances up to 10 km. The possible deposition of
virus particles has been considered, as well as some restrictive conditions influencing virus survival in the atmosphere. The results have been tested by comparison with real data corresponding to two epidemics of foot-and-mouth disease. The agreement is relatively good, although uncertainty arises from poor knowledge of the real virus excretion rate and of the exact meteorological conditions existing in the two aforementioned epidemics.